A couple of simple cues could make people waste substantially less food in places such as hotels, schools, and hospitals, researchers say.

Food waste doesn’t immediately leap to mind as a major cause of climate change. But the study authors point out that a large proportion of the world’s greenhouse gas emissions results from food production. Feeding the growing human population also leads to fertilizer pollution, depletion of the oceans, and other environmental problems. And yet some researchers estimate that about one-third of food never gets eaten.

The team decided to tackle one of the most notorious spots for food waste: the buffet. For about six weeks in 2012, seven hotel restaurants offered their diners smaller plates. Another seven hotel restaurants posted a sign saying, “Welcome back! Again! And again! Visit our buffet many times. That’s better than taking a lot once.” The study authors reasoned that this suggestion would prompt people to take smaller portions rather than loading up their plates with food they couldn’t finish.

The strategies worked, the team reports in Economics Letters. Switching to smaller plates cut food waste by 19.5 percent, and the buffet signs resulted in a drop of 20.5 percent. The researchers also analyzed the relationship between plate size and food waste across 38 hotels and found that reducing plate size by 3 centimeters was linked to 22 percent less food waste.

The measures are relatively cheap to implement and will end up saving restaurants money, the authors say. And customer satisfaction surveys suggested that the diners didn’t mind having to take smaller portions. — Roberta Kwok | 22 March 2013